Do not search for "Pegatron N14939 driver 91" as a single term. Instead, identify the actual components.
Do not rely on Windows Update if it is failing. Go to the official source.
Example: VEN_8086&DEV_5A98&SUBSYS_...&REV_... — sometimes the last digits of the subsystem ID are 91. Check in Device Manager > Properties > Details > Hardware Ids. pegatron n14939 driver 91
Believe it or not, the Pegatron N14939 driver 91 error is sometimes caused by a BIOS/UEFI mismatch. If your system shipped with Windows 7 and you upgraded to Windows 10, the ACPI tables may be corrupted.
If you want, I can:
(Invoking related search suggestions next.)
It looks like you are looking for information on the Pegatron N14939 (often labeled as "N14939" on the board) and a driver related to the number 91 — possibly a hardware ID, chipset component, or a specific driver version. Do not search for "Pegatron N14939 driver 91"
Here is a useful, practical breakdown of what this hardware is, what the "91" might refer to, and where to find the correct drivers.